Northwestern and the University of Chicago were among dozens of universities that filed briefs with the court arguing for the importance of race-conscious admissions policies.

"We are breathing a sigh of relief," said Thomas Cline, the general counsel at Northwestern. "It could have gone in a very different direction.

"There is an implicit message there from the court's conservative wing, which is that under a different set of circumstances, we might have decided that ... the use of race has no place in admissions decisions, period," he said.

At Northwestern, about 5 percent of the study body is African-American and about 6 percent is Latino, according to fall 2011 figures from the U.S. Department of Education.

Cline said the decision puts colleges and universities on notice that they will be required to show they are using affirmative action in the narrowest way possible to achieve a racially diverse student body — and that the courts will be watching.

"They are almost inviting that next case," Cline said.

Colleges and universities have vigorously defended their race-conscious policies, arguing that they consider race when admitting students in order to get the educational benefits of a diverse student body. Northwestern and other colleges use what they call a "holistic" approach when evaluating applicants and take many factors into account including grades, test scores, extracurricular activities, work experience, race and socioeconomic status.

"Many institutions do believe that having a diverse learning environment is crucial to their mission to educate the populace for this diverse world," said Ada Meloy, general counsel for the Washington, D.C.-based American Council on Education, which represents about 1,800 institutions.

U. of I. has struggled in recent years with a decline in African-American students. About 5.5 percent of undergraduates in Urbana-Champaign were African-American last year, compared with 6.9 percent a decade ago. The number of Latino students is up over the same time; they now account for about 7 percent of undergraduates.

U. of I.'s freshman class of 6,920 students last fall included about 415 African-American students, about 100 fewer than a decade ago. However, students recently were given the option to identify themselves as "two or more races" when sharing their demographic information.

In a statement after the court decision Monday, U. of I. President Robert Easter said: "The University of Illinois will continue advancing its commitment to diversity within the bounds of the law."